Accelerated dry-stack masonry construction is seen all over the world in the last two decades. Intense investigation on structural behaviour of dry-stack masonry is also seen worldwide. This research work, presents an investigation of the structural behaviour of Hydraform drystack masonry developed in South Africa. Unit compressive strength, masonry wall compressive strength and flexural resistance of dry-stack masonry/reinforced concrete beams were investigated. Due to the interlocking mechanism nature of Hydraform dry-stack blocks, three different unit compressive testing methods were investigated. The methods are described as: - Shoulder test; - Centre test; - Cube test. Tests were carried out under different humidity conditions: - Dry; - Wet; - Normal. Influence of different cement contents within the block units and moisture contents were investigated. The study made proposal of Hydraform block unit grads to be used for design. Compressive strength of dry-stack masonry walls was experimentally investigated. Dry-stack masonry wall specimens made by different block grades were subjected to in-plane vertical uniformly distributed load. Test results were used to establish dry-stack masonry characteristic compressive strength for several block grades. Flexural strength of dry-stack masonry/reinforced concrete composite beams was investigated. Series of beams were tested for flexural resistance. Applicability of conventional reinforced masonry flexural analysis philosophy was established.

Masonry is one of the oldest forms of construction materials that is still in use today. However, construction practices in the modern age demand faster and more economical practices. Dry-stack masonry, or masonry that doesn't use mortar to bind the blocks together, is a unique system to make masonry more economical. Though several systems of dry-stack masonry have been suggested little to no data exists as most of these systems are patented. This research used dry-stacked normal weight concrete masonry units with an eccentrically placed reinforcement. The wall system is connected through a surface bond and lacks any geometric connection. Previously, research has been conducted on the wall system for its axial compressive capacity, but little information is known about its ability to withstand lateral forces such as earthquakes. Research was conducted on the wall system in order to determine the seismic parameters, including the force reduction factor, overstrength factor, and the displacement amplification factor. To determine these factors the guidelines from the Federal Emergency Management Agency (FEMA) Quantification of Building Seismic Performance Factors 2009 were followed. The guidelines are explicit that both experimental data and computer modeling are needed to quantify these parameters. Experimental data was obtained from a diagonal tension test, and an in-plane shear test. The diagonal tensions test provided preliminary values on the shear modulus and shear resistance. The in-plane shear test was of primary interest and what would be used to verify the computer model. Computer modeling of the wall system was accomplished with Vector 2. Initially the computer modeling was done to reproduce experimental data. Then, a parametric study was performed using the model to see what component of the wall most effected its capacity. This analysis showed that the surface bond was the component of the wall that most affects its capacity. Finally, the computer model was run through the FEMA Far-Field earthquake suite to gather data on the strength and ductility. Values of the force reduction factor, overstrength factor, and displacement amplification factor were determined based on the time history analysis and pushover analysis on the computer model.

Student Number : 0100677A - PhD thesis - School of Civil and Environmental Engineering - Faculty of Engineering and the Built Environment / This thesis presents the findings on empirical study of dry-stack masonry. Dry-stack masonry refers to a method of building masonry walls, where most of the masonry units are laid without mortar in the joints. Of late (since mid eighties) in modern construction, dry-stacking or mortarless technology is increasingly becoming popular because of its advantages. The construction industry is acknowledging the need to accelerate the masonry construction process, as the traditional method is labour intensive and hence slower due to the presence of a large number of mortar joints. Early attempts were made to increase the size of masonry units (block instead of brick), thereby reducing the number of mortar joints, wherein the use of bedding mortar imposed constraints on the number of courses to be constructed in a day. Elimination of bedding mortar accelerates construction; thereby reducing cost, variation due to workmanship and generally small pool of skilled labour is required in dry stacking. Dry-stack masonry is a relatively new technology not yet regulated in the code of practice and therefore very limited information on the structural behaviour of the masonry is available. This project is based on the investigation of the HYDRAFORM dry-stack system, which utilises compressed soil-cement interlocking, blocks. The system is now widely used in Africa, Asia and South America. The main objective of the project was to establish through physical testing the capacity of the system to resist lateral load (e.g. wind load), vertical load and dynamic load such as earthquake loading. In the first phase of the project investigations were conducted under static loading where series of full-scale wall panels were constructed in the laboratory and tested under lateral loading, and others were tested under vertical loading to establish the mode of failure and load capacity of the system. Series of control tests were also conducted by testing series of wallettes to establish failure mechanism of the units and to establish the flexural strength of the system. Finally the test results were used for modelling, where load prediction models for the system under vertical loading and under lateral loading were developed. The theoretical load prediction models were tested against the test results and show good agreement. After the load capacity was established the next step in the study was to further improve the system for increased capacity particularly under dynamic loading. The normal Hydraform system was modified by introducing a conduit, which allows introduction of reinforcements. Series of dry-stack seismic systems were constructed and initially tested under static lateral loading to establish the lateral load capacity. The second Phase of the project was to investigate the structural behaviour and performance of the Hydraform system under seismic loading. A shaking table of 20 tonnes payload, (4m x 4m) in plan was designed and fabricated. A full-scale plain dry-stack masonry house was constructed on the shaking table and subjected to seismic base motions. The shaking table test was performed using sine wave signals excitations starting from low to very severe intensity. A conventional masonry test structure of similar parameters was also constructed on the table and tested in a similar manner for comparison. The tests were conducted using a frequency range of 1Hz to 12Hz and the specimens were monitored for peak accelerations and displacements. For both specimens the initial base motion was 0.05g. The study established the mode of failure of the system; the structural weak points of unreinforced dry-stack masonry, the general structural response of the system under seismic condition and the failure load. The plain dry-stack masonry failed at 0.3g and the conventional masonry failed at 0.6g. Finally recommendations for further strengthening of system to improve its lateral capacity were proposed.

Interlocking compressed earth blocks (ICEBs) are cement stabilized soil blocks that allow for dry stacked construction. The incomplete understanding of the inelastic performance of ICEB building systems limits widespread acceptance of this structural system in earthquake prone areas. This thesis presents results from an experimental program designed to explore the behavior of ICEB walls, built according to current design practice in Indonesia and Thailand, and subjected to out-of-plane loading. A total of five reinforced and grouted ICEB walls were constructed and tested. Results from experimentation show the current masonry design code, ACI 530, adequately predicts the yield strength of these walls. However, ACI 530 grossly over-predicts the ICEB wall stiffness. All tests showed flexural behavior and failure, except for one wall. A brittle failure was observed in one wall before reaching the predicted flexural strength, prompting a suggested maximum shear tie spacing. The testing results provide useful data for developing analytical models that predicts the seismic behavior of ICEB walls under out-of-plane loading. A moment-curvature relationship was developed that accurately predicts the behavior of these walls in the elastic range as well as the inelastic range. By comparing the data provided by two walls of similar sizes, one including a pilaster and one without a pilaster, insight into stiffener elements was gained. Analysis of these two walls provides a limit on the length and height of ICEB walls without stiffener elements to prevent significant structural damage during a seismic event. In all, conclusions based on experimental data from ICEB out-of-plane loading tests are aimed to provide suggestions for ICEB construction in areas of high-seismicity.

This thesis presents results from testing of interlocking compressed earth block (CEB) masonry shear walls. CEBs are low strength earth masonry units sometimes stabilized with cement or lime. The interlocking compressed earth blocks (ICEBs) used in this experiment are dry stacked interlocking hollow units, which can be reinforced and grouted after they are laid. Although significant research has been undertaken to optimize the material properties of CEBs, little has been done to investigate the performance of structural systems currently being built using this technology. Test results are reported for three 1800 mm x 1800 mm wall specimens constructed with cement stabilized ICEBs and subjected to cyclic in-plane lateral loading. Wall specifications were varied to identify the shear performance of partial and fully grouted walls, and to observe the performance of a flexure dominated wall panel. It was determined that the shear strength of fully grouted walls is significantly higher than that of partially grouted walls and calculation of capacity based on current ACI 530-08 masonry provisions significantly overestimates the shear strength of ICEB wall panels. Based on the observed performance, recommendations are made for limiting the calculated nominal shear strength in design. Results also indicate that calculations based on simple bending theory conservatively predict the flexural strength of a fully grouted ICEB wall. Discussion of ICEB material properties and recommendations for design and construction procedures are included.

This thesis investigates the in-plane shear performance of full-scale walls made from compressed earth blocks. Compressed earth blocks are a type of masonry where the blocks are composed of compressed soil and typically dry-stacked without mortar. Prior research has demonstrated that the in-plane shear strength of these blocks falls far short of capacities predicted by conventional masonry building codes, requiring new testing to develop effective and safe designs for seismic conditions. This thesis specifically studies the effects of block type and the use of grouted shear keys at the block head joints. Three full-scale walls were constructed and tested under in-plane, cyclic loading. To compare the effect of block type on shear strength, one wall was constructed from Rhino blocks as used by the Center for Vocational Building Technology, while another used V-Lock blocks designed by the Vermeer Corporation. Apart from differences in size and interlock mechanism, the standard Rhino blocks have shear keys at the head joints which are not present on the V-Lock blocks. To examine the effect of these shear keys, a third wall was built from Rhino blocks with the shear keys removed. The two standard block types displayed no major difference in strength that could not be attributed to grouted area or the presence/absence of the head joint shear keys. The Rhino block wall with shear keys reached a higher peak load relative to the grouted area but experienced a brittle drop in capacity after peaking, while the other two walls exhibited an extended loading plateau after the initial peak. All walls failed with cracking and block sliding along the main diagonals, a failure mode similar to conventional masonry. Proposals are made for modifying the equations for shear capacity from the Masonry Standards Joint Committee (MSJC) 2013 code for use in designing compressed earth block shear walls.

The buildings people inhabit everyday frame their existence and provide a backdrop for life. This relationship is inextricable and, as such, begs the question as to whether buildings can function as more than mere containers for life or whether they, at some point or in some capacity, can begin to bare influence over the life or quality of life of their patrons. This project is an intention to explore this qualitative, unquantifiable aspect of building. Through a manipulation of volume and mass, constriction and expansion, solid and void, light and shadow, and the qualities of interiority and exteriority an occupied space will begin to impress itself upon the user. The main objective of this project is to use these architectural properties to create a place that fosters introspection through self awareness. By choosing presence over practicality and content over convention, the construct proposed in this thesis attempts to create spaces that are imposing and unfamiliar yet somehow emotionally reminiscent. Confronted by these contradictions and juxtapositions, this building will stand as an object, in opposition to the occupant, and through that opposition inspire and promote a greater awareness of, and possibly a reflection upon, normally unconscious thought processes. / Master of Architecture

The ENDURA block system is a dry-stack surface-bonded masonry system. Typical masonry construction uses thin-set mortar in the bed joints to provide a bearing surface for the blocks while the ENDURA system typically relies on shims and a surface bonding coat to ensure that the wall is level and plumb and to provide stability. Typical ENDURA block walls are built with the reinforcement placed eccentrically in the walls. Testing was performed on ten walls in order to determine axial capacity. The walls were ten feet high by eight feet wide. Each of the walls was built using a different configuration of block type, reinforcement spacing, and amount of grout. A steel frame with two hydraulic jacks was used to apply vertical load to the top of the walls. Three conclusions were drawn from the axial testing performed. First, typical ENDURA block walls built without thin set mortar in the bed joints have similar axial capacity to walls built with the thin set mortar. Second, walls built with un-reinforced cells grouted resisted significantly more load than walls built with only the reinforced cells grouted. Third, more research is required in order to establish a control and to determine whether the eccentrically placed rebar has a significant effect on the axial capacity of the walls.

This is a project about reconciling the rational world of architecture with the empirical world of nature. A small retreat on the Appalachian Trail near Dragon's Tooth, this project employs two elements belonging to each of those entities. The retreat is composed of a double envelope. The exterior envelope is a wooden screen and dry stacked stone wall relating to the natural world. In contrast, the second envelope is a glass and steel box, analogous to the rationality of man. Dimensional 2x4 lumber models are employed to study the light conditions, patterns, and construction of the wooden screen. / Master of Architecture